Java DOM XML Parser

2024-03-19 12:38
文章标签 java xml parser dom

本文主要是介绍Java DOM XML Parser，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

DOM parser parses the entire XML document and loads it into memory; then models it in a “TREE” structure for easy traversal or manipulation.

In short, it turns a XML file into DOM or Tree structure, and you have to traverse a node by node to get what you want.

Warning
DOM Parser is slow and consumes a lot of memory when it loads an XML document which contains a lot of data. Please consider SAX parser as solution for it, SAX is faster than DOM and use less memory.

1.0 How to read XML file in Java

/Users/mkyong/staff.xml

<?xml version="1.0"?>
<company><staff id="1001"><firstname>yong</firstname><lastname>mook kim</lastname><nickname>mkyong</nickname><salary>100000</salary></staff><staff id="2001"><firstname>low</firstname><lastname>yin fong</lastname><nickname>fong fong</nickname><salary>200000</salary></staff>
</company>

ReadXMLFile.java

package com.mkyong.seo;import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import java.io.File;public class ReadXMLFile {public static void main(String argv[]) {try {File fXmlFile = new File("/Users/mkyong/staff.xml");DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();Document doc = dBuilder.parse(fXmlFile);//optional, but recommended//read this - http://stackoverflow.com/questions/13786607/normalization-in-dom-parsing-with-java-how-does-it-workdoc.getDocumentElement().normalize();System.out.println("Root element :" + doc.getDocumentElement().getNodeName());NodeList nList = doc.getElementsByTagName("staff");System.out.println("----------------------------");for (int temp = 0; temp < nList.getLength(); temp++) {Node nNode = nList.item(temp);System.out.println("\nCurrent Element :" + nNode.getNodeName());if (nNode.getNodeType() == Node.ELEMENT_NODE) {Element eElement = (Element) nNode;System.out.println("Staff id : " + eElement.getAttribute("id"));System.out.println("First Name : " + eElement.getElementsByTagName("firstname").item(0).getTextContent());System.out.println("Last Name : " + eElement.getElementsByTagName("lastname").item(0).getTextContent());System.out.println("Nick Name : " + eElement.getElementsByTagName("nickname").item(0).getTextContent());System.out.println("Salary : " + eElement.getElementsByTagName("salary").item(0).getTextContent());}}} catch (Exception e) {e.printStackTrace();}}}

Result:

Root element :company
----------------------------Current Element :staff
Staff id : 1001
First Name : yong
Last Name : mook kim
Nick Name : mkyong
Salary : 100000Current Element :staff
Staff id : 2001
First Name : low
Last Name : yin fong
Nick Name : fong fong
Salary : 200000

Looping the Node
ReadXMLFile2.java

package com.mkyong.seo;import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;public class ReadXMLFile2 {public static void main(String[] args) {try {File file = new File("/Users/mkyong/staff.xml");DocumentBuilder dBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();Document doc = dBuilder.parse(file);System.out.println("Root element :" + doc.getDocumentElement().getNodeName());if (doc.hasChildNodes()) {printNote(doc.getChildNodes());}} catch (Exception e) {System.out.println(e.getMessage());}}private static void printNote(NodeList nodeList) {for (int count = 0; count < nodeList.getLength(); count++) {Node tempNode = nodeList.item(count);// make sure it's element node.if (tempNode.getNodeType() == Node.ELEMENT_NODE) {// get node name and valueSystem.out.println("\nNode Name =" + tempNode.getNodeName() + " [OPEN]");System.out.println("Node Value =" + tempNode.getTextContent());if (tempNode.hasAttributes()) {// get attributes names and valuesNamedNodeMap nodeMap = tempNode.getAttributes();for (int i = 0; i < nodeMap.getLength(); i++) {Node node = nodeMap.item(i);System.out.println("attr name : " + node.getNodeName());System.out.println("attr value : " + node.getNodeValue());}}if (tempNode.hasChildNodes()) {// loop again if has child nodesprintNote(tempNode.getChildNodes());}System.out.println("Node Name =" + tempNode.getNodeName() + " [CLOSE]");}}}
}
2.0 How to modify XML file in Java

修改前xml file
file.xml

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<company><staff id="1"><firstname>yong</firstname><lastname>mook kim</lastname><nickname>mkyong</nickname><salary>100000</salary></staff>
</company>

修改后xml

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<company><staff id="2"><lastname>mook kim</lastname><nickname>mkyong</nickname><salary>2000000</salary><age>28</age></staff>
</company>

ModifyXMLFile .java修改xml

import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;public class ModifyXMLFile {public static void main(String argv[]) {try {String filepath = "c:\\file.xml";DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();DocumentBuilder docBuilder = docFactory.newDocumentBuilder();Document doc = docBuilder.parse(filepath);// Get the root elementNode company = doc.getFirstChild();// Get the staff element , it may not working if tag has spaces, or// whatever weird characters in front...it's better to use// getElementsByTagName() to get it directly.// Node staff = company.getFirstChild();// Get the staff element by tag name directlyNode staff = doc.getElementsByTagName("staff").item(0);// update staff attributeNamedNodeMap attr = staff.getAttributes();Node nodeAttr = attr.getNamedItem("id");nodeAttr.setTextContent("2");// append a new node to staffElement age = doc.createElement("age");age.appendChild(doc.createTextNode("28"));staff.appendChild(age);// loop the staff child nodeNodeList list = staff.getChildNodes();for (int i = 0; i < list.getLength(); i++) {Node node = list.item(i);// get the salary element, and update the valueif ("salary".equals(node.getNodeName())) {node.setTextContent("2000000");}//remove firstnameif ("firstname".equals(node.getNodeName())) {staff.removeChild(node);}}// write the content into xml fileTransformerFactory transformerFactory = TransformerFactory.newInstance();Transformer transformer = transformerFactory.newTransformer();DOMSource source = new DOMSource(doc);StreamResult result = new StreamResult(new File(filepath));transformer.transform(source, result);System.out.println("Done");} catch (ParserConfigurationException pce) {pce.printStackTrace();} catch (TransformerException tfe) {tfe.printStackTrace();} catch (IOException ioe) {ioe.printStackTrace();} catch (SAXException sae) {sae.printStackTrace();}}
}
3.0 How to create XML file in Java

要生成的xml file.xml

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<company><staff id="1"><firstname>yong</firstname><lastname>mook kim</lastname><nickname>mkyong</nickname><salary>100000</salary></staff>
</company>

WriteXMLFile .java

package com.mkyong.core;import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;public class WriteXMLFile {public static void main(String argv[]) {try {DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();DocumentBuilder docBuilder = docFactory.newDocumentBuilder();// root elementsDocument doc = docBuilder.newDocument();Element rootElement = doc.createElement("company");doc.appendChild(rootElement);// staff elementsElement staff = doc.createElement("Staff");rootElement.appendChild(staff);// set attribute to staff elementAttr attr = doc.createAttribute("id");attr.setValue("1");staff.setAttributeNode(attr);// shorten way// staff.setAttribute("id", "1");// firstname elementsElement firstname = doc.createElement("firstname");firstname.appendChild(doc.createTextNode("yong"));staff.appendChild(firstname);// lastname elementsElement lastname = doc.createElement("lastname");lastname.appendChild(doc.createTextNode("mook kim"));staff.appendChild(lastname);// nickname elementsElement nickname = doc.createElement("nickname");nickname.appendChild(doc.createTextNode("mkyong"));staff.appendChild(nickname);// salary elementsElement salary = doc.createElement("salary");salary.appendChild(doc.createTextNode("100000"));staff.appendChild(salary);// write the content into xml fileTransformerFactory transformerFactory = TransformerFactory.newInstance();Transformer transformer = transformerFactory.newTransformer();DOMSource source = new DOMSource(doc);StreamResult result = new StreamResult(new File("C:\\file.xml"));// Output to console for testing// StreamResult result = new StreamResult(System.out);transformer.transform(source, result);System.out.println("File saved!");} catch (ParserConfigurationException pce) {pce.printStackTrace();} catch (TransformerException tfe) {tfe.printStackTrace();}}
}
4.0 How to count XML Elements in Java

file.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<company><staff id="1"><firstname>yong</firstname><lastname>mook kim</lastname><nickname>mkyong</nickname><salary>2000000</salary><age>29</age></staff><staff id="2"><firstname>low</firstname><lastname>yin fong</lastname><nickname>fong fong</nickname><salary>1000000</salary></staff><staff id="3"><firstname>Ali</firstname><lastname>Baba</lastname><nickname>Alibaba</nickname><salary>199000</salary><age>40</age></staff>
</company>

CountXMLElement.java 

import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;public class CountXMLElement {public static void main(String argv[]) {try {String filepath = "c:\\file.xml";DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();DocumentBuilder docBuilder = docFactory.newDocumentBuilder();Document doc = docBuilder.parse(filepath);NodeList list = doc.getElementsByTagName("staff");System.out.println("Total of elements : " + list.getLength());} catch (ParserConfigurationException pce) {pce.printStackTrace();} catch (IOException ioe) {ioe.printStackTrace();} catch (SAXException sae) {sae.printStackTrace();}}
}
5.0 解析网络xml

AlexaSEO.java

package com.mkyong.seo;import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;public class AlexaSEO {public static void main(String[] args) {AlexaSEO obj = new AlexaSEO();System.out.println("Ranking : " + obj.getAlexaRanking("mkyong.com"));}public int getAlexaRanking(String domain) {int result = 0;String url = "http://data.alexa.com/data?cli=10&url=" + domain;try {URLConnection conn = new URL(url).openConnection();InputStream is = conn.getInputStream();DocumentBuilder dBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();Document doc = dBuilder.parse(is);Element element = doc.getDocumentElement();NodeList nodeList = element.getElementsByTagName("POPULARITY");if (nodeList.getLength() > 0) {Element elementAttribute = (Element) nodeList.item(0);String ranking = elementAttribute.getAttribute("TEXT");if(!"".equals(ranking)){result = Integer.valueOf(ranking);}}} catch (Exception e) {System.out.println(e.getMessage());}return result;}
}

这篇关于Java DOM XML Parser的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！


http://www.chinasem.cn/article/826020。

相关文章

Java学习手册之Filter和Listener使用方法

Java学习手册之Filter和Listener使用方法

《Java学习手册之Filter和Listener使用方法》：本文主要介绍Java学习手册之Filter和Listener使用方法的相关资料,Filter是一种拦截器,可以在请求到达Servl... 目录一、Filter（过滤器）1. Filter 的工作原理2. Filter 的配置与使用二、Listen
阅读更多...
Spring Boot中JSON数值溢出问题从报错到优雅解决办法

Spring Boot中JSON数值溢出问题从报错到优雅解决办法

《SpringBoot中JSON数值溢出问题从报错到优雅解决办法》：本文主要介绍SpringBoot中JSON数值溢出问题从报错到优雅的解决办法,通过修改字段类型为Long、添加全局异常处理和... 目录一、问题背景：为什么我的接口突然报错了？二、为什么会发生这个错误？1. Java 数据类型的“容量”限制
阅读更多...
Java对象转换的实现方式汇总

Java对象转换的实现方式汇总

《Java对象转换的实现方式汇总》：本文主要介绍Java对象转换的多种实现方式,本文通过实例代码给大家介绍的非常详细,对大家的学习或工作具有一定的参考借鉴价值,需要的朋友参考下吧... 目录Java对象转换的多种实现方式1. 手动映射（Manual Mapping）2. Builder模式3. 工具类辅助映
阅读更多...
SpringBoot请求参数接收控制指南分享

SpringBoot请求参数接收控制指南分享

《SpringBoot请求参数接收控制指南分享》：本文主要介绍SpringBoot请求参数接收控制指南,具有很好的参考价值,希望对大家有所帮助,如有错误或未考虑完全的地方,望不吝赐教... 目录Spring Boot 请求参数接收控制指南1. 概述2. 有注解时参数接收方式对比3. 无注解时接收参数默认位置
阅读更多...
SpringBoot基于配置实现短信服务策略的动态切换

SpringBoot基于配置实现短信服务策略的动态切换

《SpringBoot基于配置实现短信服务策略的动态切换》这篇文章主要为大家详细介绍了SpringBoot在接入多个短信服务商（如阿里云、腾讯云、华为云）后,如何根据配置或环境切换使用不同的服务商,需... 目录目标功能示例配置（application.yml）配置类绑定短信发送策略接口示例：阿里云 & 腾
阅读更多...
SpringBoot项目中报错The field screenShot exceeds its maximum permitted size of 1048576 bytes.的问题及解决

SpringBoot项目中报错The field screenShot exceeds its maximum permitted size of 1048576 bytes.的问题及解决

《SpringBoot项目中报错ThefieldscreenShotexceedsitsmaximumpermittedsizeof1048576bytes.的问题及解决》这篇文章... 目录项目场景问题描述原因分析解决方案总结项目场景javascript提示：项目相关背景：项目场景：基于Spring
阅读更多...
Spring Boot 整合 SSE的高级实践(Server-Sent Events)

Spring Boot 整合 SSE的高级实践(Server-Sent Events)

《SpringBoot整合SSE的高级实践(Server-SentEvents)》SSE（Server-SentEvents）是一种基于HTTP协议的单向通信机制,允许服务器向浏览器持续发送实... 目录1、简述2、Spring Boot 中的SSE实现2.1 添加依赖2.2 实现后端接口2.3 配置超时时
阅读更多...
Spring Boot读取配置文件的五种方式小结

Spring Boot读取配置文件的五种方式小结

《SpringBoot读取配置文件的五种方式小结》SpringBoot提供了灵活多样的方式来读取配置文件,这篇文章为大家介绍了5种常见的读取方式,文中的示例代码简洁易懂,大家可以根据自己的需要进... 目录1. 配置文件位置与加载顺序2. 读取配置文件的方式汇总方式一：使用 @Value 注解读取配置方式二
阅读更多...
一文详解Java异常处理你都了解哪些知识

一文详解Java异常处理你都了解哪些知识

《一文详解Java异常处理你都了解哪些知识》：本文主要介绍Java异常处理的相关资料,包括异常的分类、捕获和处理异常的语法、常见的异常类型以及自定义异常的实现,文中通过代码介绍的非常详细,需要的朋... 目录前言一、什么是异常二、异常的分类2.1 受检异常2.2 非受检异常三、异常处理的语法3.1 try-
阅读更多...
Java中的@SneakyThrows注解用法详解

Java中的@SneakyThrows注解用法详解

《Java中的@SneakyThrows注解用法详解》：本文主要介绍Java中的@SneakyThrows注解用法的相关资料,Lombok的@SneakyThrows注解简化了Java方法中的异常... 目录前言一、@SneakyThrows 简介1.1 什么是 Lombok？二、@SneakyThrows
阅读更多...

Copyright China编程 23002807@qq.com

沪ICP备2023033072号-2